Dyeing of Wool Fibres

ABSTRACT

The present invention relates to a process for dyeing fibre materials composed of wool wherein an alkoxylated and quaternized fatty acid amine, preferably a quaternized, ethoxylated oleylamine, is used as a levelling agent. The present compound leads to very uniform dyeings and is very effective in low concentrations.

This invention relates to a process for dyeing wool or wool-containing materials with the aid of a levelling agent to obtain uniform dyeings.

Levelling agents or assistants are generally surface-active textile dyeing auxiliaries which have the task of thoroughly wetting the fibre/fibre blend to be dyed, of promoting penetration of the fibres and of preventing too rapid uptake of the dyes, which can lead to unlevelness (spottiness), during the dyeing operation. Suitable levelling assistants include oleylsulphonates, fatty alcohol sulphonates, various fatty acid condensation products, alkyl and alkylaryl polyglycol ethers and surface-active chemicals in general.

Unlevelness is caused by:

-   -   High and varying substantivity of the dye on the fibre     -   High and varying affinity of the fibre for the dye     -   Uneven distribution of the dye solution on the fibre     -   Temperature differences on the fibre

Insufficient levelness can be prevented by means of suitable dyeing techniques (including improving the diffusion of the solution within the fabric, pH control) and by means of levelling assistants.

Levelling assistants reduce mainly the rate of dyeing, increase the rate of dye migration within the fibre and improve the compatibility of the dyes.

Levelling agents can also have other effects which have no direct influence on the dye-fibre interactions, but nevertheless exert a positive effect on the dyeing. These include the improved solubility or the dispersion stability of the dye.

Levelling assistants can exert two or more of the abovementioned effects at the same time.

Levelling assistants can be divided into two groups, those which have an affinity for the fibre and those which have an affinity for the dye.

Levelling assistants with an affinity for dyes form an addition compound with the dye whose stability is concentration dependent and normally decreases with increasing temperature.

The dye distribution equilibrium between the dye in solution and the dye in the fibre is therefore shifted to the dye in solution. The increased dye concentration in the dye solution makes it possible for regions of the fabric which were dyed in a non-level manner to level out as a result of dye migration.

Effective levelling assistants have an affinity for the dye that is sufficient to reduce the absorption rate or to speed the migration rate. Differences in the absorption behaviour of different dyes can likewise be levelled, so that the dyes in a dye mixture can go on at a uniform rate.

Assistants with an affinity for dyes can also be used to level previously dyed materials. Assistants with an affinity for fibres go onto the fibre in competition with the dye. This competition reaction reduces the absorption rate and promotes the migration rate.

Important dye-affinity levelling assistant types for wool are nonionic surfactants or weakly cationic, ethoxylated compounds.

Important fibre-affinity levelling assistant types for wool are anionic compounds.

Levelling assistants used for wool are frequently ethoxylated amine compounds, partially quaternized, as disclosed for example in DE-A-28 41 800.

Yet there still continues to be a need for even more effective levelling agents.

It has now been found that, surprisingly, quite specific quaternized and ethoxylated amine compounds based on unsaturated fatty acids are very useful as levelling agents for wool.

The present invention accordingly provides a process for dyeing fibre materials composed of wool, characterized in that one or more compounds of formula (I)

-   -   where     -   R is singly or doubly unsaturated alkenyl of 12 to 24 carbon         atoms,     -   X⁻ is an anion, and     -   (n+m) has an average value in the range from 14 to 29,     -   are used as active substance of a levelling agent.

The above process is advantageous when

-   -   R is a radical derived from oleic acid, linoleic acid or         linolenic acid,     -   X⁻ is chloride, bromide, iodide, methosulphate, sulphate,         phosphate or acetate, and     -   (n+m) has an average value in the range from 17 to 19.

Preferably, the active substance is a compound of formula (II)

-   -   where     -   (n+m) has an average value in the range from 17 to 19.

Advantageously, the active substance is used as an aqueous solution wherein the concentration of active substance is in the range from 15% to 35% by weight.

It is particularly advantageous when the concentration of active substance in the aqueous solution is in the range from 25% to 35% by weight and when 0.1% to 5% by weight of foam-suppressing substances are included as further additives.

Depending on the dye, the dyeing is usually carried out at a pH in the range from 2 to 9, preferably in the range from 3 to 8, and especially in the range from 4 to 7.

It is further advantageous when the liquor ratio is in the range from 2:1 to 80:1 in the case of a batch dyeing, preferably in the range from 5:1 to 30:1, and in the range from 5:1 to 500:1 in the case of a continuous dyeing, preferably in the range from 20:1 to 300:1.

X⁻ represents a customary inorganic or organic anion such as halides (chloride, bromide, iodide), sulphate, methosulphate, phosphate or acetate. Chloride is preferred.

The present active substance is known (CAS No. 747377-35-1 and 133189-76-1) and is simple to prepare by alkoxylation of the corresponding fatty amine. The alkoxylation can also be carried out with propylene oxide instead of ethylene oxide or ethylene oxide and propylene oxide, randomly or as a block, but ethoxylated amines give better results. Furthermore, the alkoxylate obtained could be completely or partially sulphonated or sulphated, although here too the non-sulphonated and non-sulphated species demonstrate better efficacy. The active substance contains in general 15 to 30 ethylene oxide (EO) units, preferably 17 to 19 EO. The active substance is particularly preferably an oleylamine with 17 to 19 EO, which was quaternized with 1 EO and contains chloride as counter-ion.

As well as the foam-suppressing substances mentioned, further additives can be used such as biocides, if desired or necessary dispersing assistants or wetting agents, for example sulphonated or sulphated alkyl, alkenyl or aryl polyglycol ethers, sulphonated or sulphated alkyl, alkenyl or aryl amine polyglycol ethers, and if desired or necessary defoamers based on silicone oil or mineral oil. It is preferable to use 2-ethylhexylisononanamide as foam-suppressing substance and a C₁₂₋₁₅-alcohol with 8 ethylene oxide and 4 propylene oxide units as wetting component with an additional foam-suppressing effect.

The present levelling agent is not only advantageous in relation to the reactive dyes used in the examples which follow, but also displays good efficacy in relation to the dyeing of wool with acid dyes.

EXAMPLES

The examples which follow illustrate the invention. Unless otherwise stated, parts and % are by weight.

Test Methods

Some test methods well known to one skilled in this art will now be described.

Ross-Miles Foam Test

-   -   The volume of foam is measured after a certain amount of liquid         has been poured from a certain height, instantly and also after         a one minute wait.     -   A 1000 ml graduated cylinder 60 mm in internal diameter and 430         mm in internal height is used. The test liquid is allowed to         pour out from a 2 l separating funnel through a capillary 70 mm         in length and 2 mm in internal diameter from a height of 600 mm,         measured from the outlet of the capillary above the floor of the         cylinder.     -   500 ml of the solution to be tested are filled into the         separating funnel and allowed to flow out into the graduated         cylinder at the capillary-controlled efflux rate of about 0.17         l/min. As soon as the entire solution has flowed out, a stop         watch is started and the entire volume (foam volume plus         solution volume) is read off the cylinder scale. The reading is         repeated after one minute.     -   The alkaline foam performance is tested using a surfactant         concentration of 2 g/l in 2° Bé—NaOH solution in demineralized         water, with 2° Bé—NaOH being equivalent to 12 g/l NaOH solid or         30 ml/l of 36° Bé NaOH. The test temperature is in the range         from 20 to 25° C.

Foam Test by Continuous Flow Method

Material: 1 tall graduated cylinder, peristaltic pump, rubber hose, 2 glass tubes, 1 long one reaching from 1 cm above the floor to the end of the cylinder and which is connected by a rubber hose, which leads through the pump, to a short, second glass tube situated at the level of a typical Ross Miles apparatus. Concentration: 2 g/l surfactant test solution in neutral or alkaline medium Procedure: 1.00 g of surfactant is dissolved at room temperature (always exactly the same) in exactly 500 ml of deionized water and stirred until a homogeneous solution or mixture is obtained. This mixture is carefully introduced into the 1 l graduated cylinder (previously washed out with deionized water), so that no foam is formed. A glass tube transports the solution from the floor (1 cm above) of the cylinder through a rubber hose by means of a peristaltic pump to the second glass tube, where the solution falls into the cylinder. The solution is continuously recirculated at 180 ml/min. The foam height after 1 minute, 5 minutes and 10 minutes is noted. The pump is stopped after 10 minutes. The foam height 1 minute after the pump has been switched off is noted as well.

Levelling Effect in Reactive Dyeing of Wool Material

Wool gaberdine, prewashed.

Apparatus

Colorstar from Mathis with special insert for columns

Dyeing Conditions

Liquor ratio 15:1; demineralized water

Through flow: 35 ml/min (5 l/min.kg=⅓ circulation/min)

Dye

Dyeing was carried out using various concentrations (⅓ and 1/1 standard depth of shade) of mono- and polyfunctional reactive dyes, for example Reactive Yellow 125, Reactive Yellow 176, Reactive Red 49 or mixtures thereof (Drimaren® dyes from Clariant) and also with Drimaren® Blue W-RL.

Dyeing Liquor

Levelling agent x x % Glauber salt calc. 5 5 % Sodium acetate cryst. 1 1 g/l Acetic acid pH 5 5 x = without and with increasing amounts of levelling agent (for example 1 and 3%)

Dyeing Procedure

The liquor is introduced into the dyeing apparatus followed, after the flow has stabilized, by the textile material. After heating with full power at room temperature to 98° C., the fabric is treated at 98° C. for 15 min, and then cooled back down to 70° C. and subsequently rinsed with cold water for 10 min.

Assessment

The fabric columns are illustrated as follows:

Sample taken: The fabric column is divided into 4 equal parts. Sample taking from the column: bottom, after ¼, ½, ¾ and top. Evaluation: The penetration of the substrate column is evaluated.

The assessment is done visually against the product to be compared.

Skitteriness Test in Reactive Dyeing of Wool Material

Loose wool fibre washed, ready for dyeing, untreated wool

Apparatus

Turby from Mathis with device for dyeing loose substrates

Dyeing Conditions

Liquor ratio 20:1; demineralized water

Circulation level 10

Dye

Dyeing was carried out with the same dyes and concentrations as in the preceding test series.

Dyeing Liquor

Levelling agent x x % Glauber salt calc. 5 5 % Sodium acetate cryst. 1 1 g/l Acetic acid pH 5 5 x = without and with increasing amounts of levelling agent (for example 1 and 3%)

Dyeing Procedure

The loaded material-carrier is introduced into the dyeing apparatus, followed by the dyeing liquor. 5 min at room temperature are followed by heating at 1° C./min to 98° C., dyeing at 98° C. for 60 min, then cooling down to 70° C. and subsequently rinsing with cold water.

Aftertreatment

The previously rinsed dyeings are aftertreated as follows on the same dyeing apparatus without intervening drying:

ammonia solution 1 ml/l conc. about 25% pH 8.5-9.0 (care must be taken to ensure that the pH stays in this range during the treatment time)

Start at room temperature, heat at full power to 85° C., treat for 20 min, then rinse cold.

Evaluation

The loose wool fibre, now dyed, is evaluated visually. The purpose of the skitteriness assessment is to even out the hue and/or depth of shade difference between the wool root and the wool tip.

Rating Against Dyeing without Levelling Agent:

No improvement, slight improvement (still distinct difference between root/tip but significantly less than without levelling agent, distinct improvement (very small differences between root/tip), good (no differences between root/tip)

Colour Build-Up Enhancement in Reactive Dyeing of Wool Material

Wool gaberdine, prewashed

Apparatus

Vistacolor from Mathis with device for piece dyeing

Dyeing Conditions

Liquor ratio 20:1; demineralized water

Stroke level 10, with twist

Dye

Dyeing was carried out with the same dyes and concentrations as in the preceding test series.

Dyeing Liquor

Levelling agent x x % Glauber salt calc. 5 5 % Sodium acetate cryst. 1 1 g/l Acetic acid pH 5 5 x = without and with increasing amounts of levelling agent (for example 1 and 3%)

Dyeing Procedure

The dyeing beakers filled with dyeing liquor are introduced into the dyeing apparatus, followed by the wool gaberdine on the material-carriers. 5 min at room temperature are followed by heating at 1° C./min to 98° C., dyeing at 98° C. for 60 min, then cooling down to 70° C. and subsequently rinsing with cold water.

Aftertreatment

The previously rinsed dyeings are aftertreated as follows on the same dyeing apparatus without intervening drying:

ammonia solution 1 ml/l conc. about 25% pH 8.5-9.0 (care must be taken to ensure that the pH stays in this range during the treatment time)

Start at room temperature, heat at full power to 85° C., treat for 20 min, then rinse cold.

Evaluation

The wool gabardine, now dyed, is evaluated calorimetrically (relative colour strength and residual colour difference).

Rating Against Dyeing without Levelling Agent:

No colour deepening, slight enhancement of depth of shade (0-25%), distinct enhancement of depth of shade (25-40%), good (40-100%)=

*****=excellent

****=very good

***=good

**=ok

*=poor

−=very poor

Products Tested: Example 1

The utilized active substance (AS) had the following formula:

Formulation: 34.5% of AS, 1.08% of C₁₂₋₁₅-alcohol with 8 ethylene oxide and 4 propylene oxide units, 0.12% of ethylhexylisononanamide, remainder water.

Example 2

The same active substance as in Example 1 was used.

Formulation: 34.5% of AS, 1.08% of C₁₂₋₁₅-alcohol with 8 ethylene oxide and 4 propylene oxide units, 0.12% of ethylhexylisononanamide, 2.0% of cumene sulphonate (40% in water), remainder water.

Example 3 Comparative Example

The utilized active substance had the following formula where X⁻ is chloride:

Formulation: 40% of AS in water

Example 4 Comparative Example

The active substance utilized was a compound as described in DE-A-2 841 800

Summary of Evaluations

None 1.0% 3.0% 1/3 1/1 1/3 1/1 1/3 1/1 Example 1 Continuous foam 0 70/10 70/10 test Levelling effect − − **** **** ***** ***** Skitteriness test none none distinct distinct distinct distinct Colour deepening — — slight good none good Example 2 Continuous foam 0 60/5  60/5  test Levelling effect − − **** **** ***** ***** Skitteriness test none none distinct distinct distinct distinct Colour deepening — — slight good none good Example 3 (comparison) Continuous foam 0 >500/>500 >500/>500 test Levelling effect − − *** **** **** ***** Skitteriness test none none distinct distinct distinct distinct Colour deepening — — none good none good Example 4 (comparison) Continuous foam 0 >500/>500 >500/>500 test Levelling effect − − *** *** *** *** Skitteriness test none none distinct distinct distinct distinct Colour deepening — — slight good slight good

All inventive examples were better than prior art products. 

1. A process for dyeing a fiber material composed of wool, comprising the step of contacting the fiber material with at least one compound of formula (I)

wherein R is singly or doubly unsaturated alkenyl of 12 to 24 carbon atoms, X⁻ is an anion, and (n+m) has an average value in the range from 14 to
 29. 2. A process according to claim 1, wherein R is a radical derived from oleic acid, linoleic acid or linolenic acid, X⁻ is chloride, bromide, iodide, methosulphate, sulphate, phosphate or acetate, and (n+m) has an average value in the range from 17 to
 19. 3. A process according to claim 1, R is a radical derived from oleic acid. X⁻ is chloride, and (n+m) has an average value in the range from 17 to
 19. 4. A process according to claim 1, wherein the compound of Formula I is in aqueous solution in the range from 15% to 35% by weight.
 5. A process according to claim 4, wherein the concentration of the compound of Formula I is in the aqueous solution is in the range from 25% to 35% by weight and wherein the aqueous solution further comprises 0.1% to 5% by weight of at least one foam-suppressing substance.
 6. A process according to claim 1, wherein the contacting step is at a pH in the range from 2 to
 9. 7. A process according to claim 1, wherein the liquor ratio of the contacting step is in the range from 2:1 to 80:1 in the case of a batch dyeing and in the range from 5:1 to 500:1 in the case of a continuous dyeing.
 8. A process according to claim 1, wherein the liquor ratio of the contacting step is in the range from 5:1 to 30:1 in the case of a batch dyeing and in the range from 20:1 to 300:1 in the case of a continuous dyeing.
 9. A fiber material dyed by the process according to claim
 1. 